As motivations from a manager go, warning players that any complacency would be punished by non-selection for the Camp Nou is obviously effective.

Neil Lennon has watched his Celtic players toil to find an adequate tempo or concentration at times on the domestic front this season. In contrast, Lennon's team have enjoyed a fine time in the Champions League.

Lennon made it clear before the trip to Paisley that he would pay particular attention to the attitude of his players. Any shortcomings, the manager insisted, would be taken into account with regards Celtic's side for Tuesday's eagerly anticipated European fixture in Barcelona.

Lennon was not let down, by virtue of Celtic's most handsome win and bullish performance of their Scottish Premier League campaign to date. Celtic raced into an unassailable 4-0 lead within 38 minutes, guaranteeing that they will travel to Catalunya high on confidence and at the summit of the table.

The blunt reality of this game was that Celtic performed very well, while St Mirren were dismal in virtually every department. With that in mind, the result was a foregone conclusion.

For Lennon, who headed from this match immediately to Spain to take in Barcelona's match at Deportivo de La Coruña, this was an almost perfect Champions League precursor. One minor concern for the manager was the second-half groin injury collected by Lassad that forced the Tunisian from the field.

But for glaring misses by Joe Ledley and Efe Ambrose, the visitors could have further embarrassed St Mirren by the interval. This, it must be noted, was from a Celtic side who were missing the influential Scott Brown, James Forrest, Georgios Samaras and Kris Commons. Lennon hopes to be able to call on at least some of that quartet once again by the time Tuesday arrives.

Celtic's intent was evident after only two minutes. Tony Watt, who was to have an effective 90 minutes rewarded by a goal, was narrowly beaten to a through ball by the St Mirren goalkeeper Craig Samson.

A Celtic advantage was soon secured, if only after St Mirren passed up their solitary chance of the early exchanges. Lewis Guy was wasteful in directing his volley straight to the hands of Fraser Forster.

Samson was helpless, and woefully exposed by his defenders, as Gary Hooper turned home a Lassad cross at close range. St Mirren's back line was even more shambolic when failing to deal with a Charlie Mulgrew free-kick; the unchallenged Ambrose duly knocked home No2.

Victor Wanyama scored the first of his two strikes from an Adam Matthews corner. Once again, the generosity of the St Mirren defence had to be seen to be believed.

There was, in fairness, little they could do about Wanyama's second and Celtic's fourth. The Kenyan swerved a wonderful effort past Samson from 30 yards, adding class to the Celtic procession. There was one of them from the home support by this stage – towards the exits.

There was little surprise attached to the fact the second half proved something of a nonevent. Or, indeed, that St Mirren summoned enough professional pride to improve.

Steven Thompson came closest to pulling a consolation goal back after 67 minutes but was denied by a fine save from Forster. Given the level of work he will almost certainly have to undertake in Barcelona, the goalkeeper may have been glad of at least some action.

Watt, a young striker of potential, headed the goal his display deserved when he met an Emilio Izaguirre cross. Wanyama was denied a hat-trick only by the St Mirren crossbar in stoppage time, with Samson also saving a Hooper header.

Barcelona will provide Celtic with an altogether different level of opposition but the SPL champions will at least travel in glowing spirits.